1. Field of the Invention
This invention relates generally to tape cassettes and more particularly is directed to improvements in tape cassettes for protecting the tape contents thereof, when not in use, and for ensuring the proper positioning of the tape cassette in respect to a cassette loading mechanism by which the cassette is positioned on magnetic recording and/or reproducing apparatus.
2. Description of the Prior Art
The use of tape cassettes in magnetic recording and/or reproducing apparatus has been expanding steadily as a result of the protection afforded to the tape and the ease with which the tape can be loaded on the apparatus for a recording or reproducing operation. Initially, tape cassettes were used in connection with magnetic recording and reproducing apparatus of the type having a fixed magnetic head projected into the cassette housing through a relatively small window. However, it has recently been proposed to employ tape cassettes in apparatus of the type having one or more rotary magnetic heads, for example, as in magnetic tape apparatus for recording and reproducing video signals. Particularly in the latter case, it is necessary that the tape cassette be easily and accurately positioned on the apparatus in order to ensure the reliable operation of an associated tape loading device by which the tape is withdrawn from the cassette housing and wrapped about a cylindrical guide drum for scanning in oblique tracks by the rotary magnetic head or heads associated with such drum.
When the recording and reproducing of signals on the tape is effected by a rotary magnetic head or heads, as above, it is necessary to provide the cassette housing with an opening through which the tape can be withdrawn by a tape loading device for engagement with such head or heads. In an existing cassette of the foregoing type, for example, as disclosed in U.S. Pat. No. 3,735,939, issued May 29, 1973, and having a common assignee herewith, the cassette is provided with a lid which is normally spring biased to cover the tape extending across the opening of the cassette housing when the cassette is not in use. U.S. Pat. No. 2,941,741 discloses a similar tape cassette in which an opening extends along the entire length of one side of the cassette housing and a lid is provided for normally covering all of such opening.
Cassette loading mechanisms provided for receiving a tape cassette and moving the latter to an operative position on a magnetic tape recording and/or reproducing apparatus are variously arranged for receiving the tape cassette in the holder by sliding of the cassette either in the direction parallel to the side of the cassette housing having the opening therein or in the direction perpendicular to that side of the housing. However, existing tape cassettes are suitable to be inserted into a holder in only one of the described directions, for example, in the direction perpendicular to the side of the cassette housing having an opening therein, as in U.S. Pat. No. 3,735,939. The aforesaid tape cassettes are also provided with a latching mechanism for locking the lid in its closed position when the cassette is not in use, and such latching mechanism is adapted to be released in response to the sliding movement of the cassette into the respective holder. However, such release of the locking mechanism requires the insertion of the tape cassette in a single direction into the holder. Thus, the existing tape cassettes are not suitable for use in connection with the various available cassette loading mechanisms having holders adapted to receive the cassettes in either of the described directions.